It's worth mentioning that in some US states, owners of single-member LLCs are not afforded asset protection, so you may need for form another kind of entity. It's also worth mentioning that owner-managers of businesses held in any entity type can still be sued individually for acts they take as a manager or officer of the business.
Hello! LLCs are required to make quarterly estimated tax payments based on their actual or estimated revenue for that quarter. At year end, you'd file a return and any over/ under will be settled at that time. So technically an LLC is not required to pay taxes in advance as quarterly payments would be made at a quarter end.
Hello! Yes absolutely, you wouldn't have to register as a separate entity unless you specifically wanted to. But if you are making money off of the publication, it would be better to have it set up as a business in order to gain tax advantages. I hope this helps!